Sweet potatoes provide late-season gardening bliss

Sunday

Sep 26, 2010 at 12:01 AMSep 26, 2010 at 7:00 AM

Jan Wiese-Fales

After repeatedly being nibbled off by deer in the early part of the season, my sweet potatoes staged a recovery and are now among the most beautiful and promising things still growing in the vegetable garden. I understand looks can be deceiving because all the really important stuff is hidden beneath the garden soil, and I know without a doubt this summer’s weather hasn’t provided the orange root crop with optimum growing conditions. But ignorance is bliss, and after so many lackluster veggie performances in this year’s garden, I’m taking my bliss wherever I can find it.

Humans have been growing sweet potatoes for centuries. No one disputes that they originated in Latin America, but genetic research casts doubt on the long-held belief that they originated in the Andes of South America, pointing instead to roots (pun intended) in Central America. Scientific records show sweet potatoes were domesticated in Peru as early as 2500 B.C.

Sweet potatoes are neither potatoes nor yams. Potatoes are tubers in the Solanaceae family, and yam tubers belong to the Dioscoreaceae family. Sweet potatoes are not tubers but rather swollen roots and are members of the Convolvulaceae, or morning glory, clan. At some point, people began to refer to sweet potatoes as yams, sometimes to differentiate between the darker-colored varieties and the lighter-fleshed ones. It eventually became common to use the names interchangeably. The U.S. Department of Agriculture does require veggies labeled as yams to include the name sweet potato in small print somewhere on product packaging.

Though they have long been a traditional Thanksgiving side dish, their consumption on the November holiday has been some people’s only experience with the sweet-fleshed vegetable — often sweetened even further with brown sugar and, if my childhood experience is any indication, marshmallows. Sweet potatoes are experiencing a surge in demand, in large part because of the popularity of sweet potato fries. A consumer study that appeared in the National Sweet Potato Council’s summer newsletter showed 57 percent of respondents dined on the orange fries at least once a month. Count me in.

A per capita potato consumption comparison of sweets versus whites in the newsletter shows between 1998 and 2008 plain old potato consumption declined 13.7 percent while sweet potatoes saw an increase of 31.5 percent.

Sweet potatoes are so packed with nutrition that even fried the health benefits of eating them outweigh current consumer rejection of fried foods. Totaling the percentages of recommended daily allowances for vitamins A and C, foliate, iron, copper, calcium and fiber, sweet potatoes beat out raw carrots and broccoli. A single sweet potato provides more fiber than a bowl of oatmeal, and one large orange root contains only 164 calories.

In many instances around the world, easily adaptable sweet potato plants have saved lives. They are ranked as the planet’s seventh most important food crop behind wheat, rice, maize, potato, barley and cassava. China produces 117 million of the 133 million tons annually grown worldwide, but almost half of them are used to feed livestock. The United States produced 900,000 tons in 2009, with North Carolina ranking as the top sweet potato producer. Alabama, Mississippi, Louisiana and California also grow significant crops.

Researchers at North Carolina State University are experimenting with genetic modifications to sweet potatoes that will lead to their use in the creation of biofuels, believing them to eventually be a more viable source of ethanol than corn.

NC State is also the home to the “Sweet Caroline” series of ornamental sweet potatoes that have become all the rage for container gardening. For more than a dozen years, the university’s breeding program has grown and improved variations of these vining beauties in lovely shades of lime green, red and purple. In July 2009, the university licensed the exclusive rights for the series to Proven Winners North America, making them broadly available to ornamental gardening consumers.

A very successful planting of Sweet Caroline purple has filled the base and spilled over the edges of my red tire planter — at the feet of a large purple elephant ear and red and yellow striped cannas. It’s a beautiful thing.

I can only hope the Vardemans — my favorite culinary sweet potato variety — planted down in the vegetable patch make me as happy when I finally have the nerve to set foot to spade.

Never miss a story

Choose the plan that's right for you.
Digital access or digital and print delivery.